Biometric authentication such as fingerprint authentication or vein authentication is a personal identification method which utilizes a difference in individual fingerprint pattern or individual vein shape.
In recent years, biometric authentication is employed in access management such as entry/exit management of a building, log-in management of a personal computer, and identity authentication at a bank ATM (Automated Teller Machine).
In biometric authentication, authentication is generally performed between a user (a person to be authenticated or certified) and an authentication device (authenticator) in the following manner.
In the registration step, the user registers his or her biometric information with the authentication device in advance.
In authentication, the user presents his/her biometric information to the authentication device.
The authentication device collates the presented biometric information with the registered biometric information. If the similarity degree between the two pieces of information satisfies a certain condition, the authentication device determines that the user is the correct user. If not, the authentication device determines that the user is a different person.
In this biometric authentication, it is desired that the biometric information be protected since it is privacy information that is characteristic of an individual.
Hence, a method of performing biometric authentication without revealing the biometric information itself has been proposed (for example, Patent Literature 1). According to this method, in registration, encrypted biometric information is registered, and in authentication, encrypted biometric information is collated.
As an encryption algorithm that can be used for encryption of biometric information, for example, encryption algorithms disclosed in Non-Patent Literatures 1 to 4 are available.